This poisoning is caused from a substance called ‘tannins’ contained within acorns themselves, but also found in oak tree leaves, young shoots, and even the bark. 

Stock usually get ill from eating the acorns. Unripe acorns are a lot more toxic, so pay close attention to strong winds bringing down crops of acorns before they’re naturally ready to drop. 

Cattle and sheep are more likely to ingest acorns in an area when feed is tight, however, any exposure to acorns or oak trees could lead to issues. 

Clinical signs of acorn poisoning are vague and often hard to spot, but are quite severe. The tannins initially cause damage to the intestinal tract, which may go unnoticed at first. However, it’s the severe damage to the kidneys that will cause the most life threatening problems, usually starting to develop within 3-7 days after ingestion. 

Animals will become depressed and go off feed, with symptoms including abdominal discomfort, diarrhoea and increased urination. The poisoning eventually leads to death, which may occur up to four weeks after ingestion. There’s no cure for this nasty issue, so prevention is the best medicine.

If you have oak trees on your farm, keeping animals fenced away from these areas is the best way to avoid any problems – particularly in autumn when acorns typically fall.